Privacy is fundamental to trusted collaboration and interactions to protect against malicious users and fraudulent activities. It is difficult to even impossible to preserve privacy in peer to peer large distributed system. In such networks, privacy is needed to protect the source of information, the destination (end user) of information, the route of information transmission and dissemination, and information content itself. <p>Privacy is an illusive subject. The semantic of information itself changes with time, context, and interpretation by humans. Exact replica of private information is not available. Even the original source of the information can not present a coherent interpretation if asked to present the information twice. It may be true for numerical data but the context in which the data needs to be used may change with time. It is hard to specify the policies for privacy preservation in a legal, precise, and correct manner. It is even harder to enforce the privacy policies.</p>